jim lehrer moderates from the university of denver. watch and engage with c-span, with our live preview at 7:00 p.m. eastern, followed by two ways to watch the debate at 9:00. on c-span2, and falling, your reactions. follow our live coverage on c- span, c-span radio, an online act c-span.org. >> at the un general assembly this week, president obama addressed the recent violence in the middle east and the death of u.s. ambassador chris stevens, who was killed in libya. on iran, the president said the u.s. would do what they must to prevent iran from acquiring a nuclear weapon. his remarks were about 30 minutes. [applause] >> on behalf of the general assembly, i would be honored to welcome to the united nations, his excellency, barack obama, president of united states of america and invite him to address the assembly. >> mr. president, mr. secretary-general, fellow delegates, ladies and gentlemen, i would like to begin today by telling you about an american named chris stevens. chris was born in a town in california. the son of a lawyer